A further Russian military intervention in Ukraine would not only be damaging to the security of both Ukraine and Europe. It could also entail significant military-strategic risks for Russia, reducing its military options in other strategic directions such as Central Asia and the Caucasus.

While Russian officials still claim they have a one-million-strong army, it may still face military-strategic overstretch should the Kremlin decide to launch extended combat operations in Ukraine. What are the reasons for this? What military options are available to secure Russia from perceived threats in its western strategic direction? What risks do operations beyond Crimea entail? A closer look at the military-strategic issues is warranted, beginning with the Russian threat assessment and peacetime military posture; however, other Russian rationales for intervention in Ukraine – such as political and economic considerations – are excluded. Our analysis presupposes that Russia expects a large-scale military intervention in Ukraine to be challenged by armed resistance. This could be in either the form of regular Ukrainian armed forces units or, perhaps more likely, irregular military forces using partisan warfare methods; the capabilities of Ukraine’s armed forces, or any capabilities of notional irregular forces, are also not examined here. NATO or another third party force intervention is not likely to be anticipated in the near term by Moscow.

Russia’s military options in UkraineAccording to Russia’s 2010 Military Doctrine, eastward enlargement of NATO is a military danger. Given this view, NATO bases in Belarus or eastern Ukraine would be an existential threat to Russia. EU membership, or even an association agreement, could be regarded by Moscow as a first step towards NATO membership. This could be pre-empted by Russia taking territory by force, thus denying it to NATO. Russia, however, may lack the military forces to secure enough Ukrainian territory as a long-term strategic buffer zone against NATO without taking significant military-strategic risks. Russia’s armed forces are nominally impressive in size, but, based on Russia’s current threat assessments, are spread thinly over the country’s enormous territory in peacetime.

Russian strategic and doctrinal documents reveal a world view that sees military threats and dangers from all directions. Apart from NATO expansion to Russia’s west, instability looms in the Caucasus and Central Asia to the south. Furthermore, Russia’s force posture in the Eastern Military District (MD) clearly shows that China is a military concern, requiring preparations to augment Russian forces there. Although the armed forces are geographically dispersed, Russia can concentrate forces for offensive operations to seize and hold territory but only in one strategic direction at a time.

For an area the size of eastern Ukraine, the forces Russia can muster for an offensive operation may be enough for it to take territory. The relatively open terrain and the mainly pro-Russian urban population in eastern and southern Ukraine both favour Russia’s regular warfare capabilities. However, Russian planners may still consider the available forces too few to successfully control such a large territory, in the face of Ukrainian armed resistance, in contrast to the operation in Crimea.

The military-strategic goal of a buffer zone could, however, be achieved by a more indirect approach. Russia’s available forces could be used for further destabilisation operations in Ukraine. Prolonged instability would prevent Ukraine joining NATO and serve to weaken the government in Kiev, which could facilitate further Russian piecemeal annexations of Ukrainian territory. How, then, could Russia use military means for such destabilisation operations? There are two main options: the first is to repeat the Crimea operation in other parts of Ukraine; the second is to expand the Crimea operation by occupying southern Ukraine.

Repeating the Crimea operationRussia has so far used its armed forces against Ukraine in three ways. First, they were used for direct – but semi-covert – intervention to capture Crimea. This prevented Ukraine, and other actors, from intervening by force. Second, a major readiness exercise was held in the Western and Central MDs from 26 February to 7 March. This served as a diversion that hindered Ukraine from focusing political and military attention on Crimea. An early Ukrainian military response in Crimea was likely to have been a Russian military concern. Finally, the stated size of the exercise signalled the potential to intervene on a larger scale, thus putting pressure on Ukraine.

Russia could once more use semi-covert operations and fast-emerging pro-Russia ‘self-defence forces’ to intervene. Continued exercise activities near Ukraine would serve both as diversions and to maintain the threat of a large-scale invasion of Ukraine. The latter could also stimulate the migration of non-ethnic Russian populations from threatened areas facilitating, to all intents and purposes, the de facto acquisition of Ukrainian territory. Possible areas where Crimea-style operations could be used to further destabilise Ukraine include key cities in the east such as Kharkiv, Donetsk and Luhansk. Another option could be to secure access to the breakaway Moldovan region of Transnistria by seizing Odessa and its hinterland towards Moldova. That would also facilitate making Transnistria a part of Russia.

Signs of preparation for such operations in those regions could include expressions of separatist aspiration and demands for increased autonomy, in combination with pro-Russia demonstrations receiving wide media coverage in Russia. Increasing unrest would be followed by the forming of ‘self-defence militias’, perhaps bolstered by volunteers primarily from Russia. At the same time, Russia would loudly express concern about the security of its compatriots. This could be used in several locations at the same time, accompanied by Russian troop movements or exercises along Ukraine’s border as diversions. The final step would be the appearance of Russian soldiers without national or unit insignia in the selected area of operation.

It should be noted that these kinds of semi-covert military operations may not conflict with a Russian diplomatic and political effort to achieve the federalisation of Ukraine. Skilfully executed it could, in fact, strengthen the political fragmentation of Ukraine, making a new constitution based on federalism the most viable option for keeping the country together.

Expanding the Crimea operationRussia could also destabilise Ukraine by expanding the Crimea operation further into Ukrainian territory, citing military-operational reasons. One such reason would be to secure a buffer zone for the newly annexed Crimea. Another would be to secure supply infrastructure for the military units and the population on the peninsula. The latter could be more ambitious and entail securing the area from the Russo–Ukrainian border near Novoshakhtinsk to the Dnieper River near Energodar, down to Kherson and along the coast, holding on to a territory covering up to 100 by 600km (see map). Territorial control would become a substantial task. In addition, although the Dnieper and the Black Sea form a natural border for this area, the line between the Russo-Ukrainian border and the Dnieper, some 300km of fairly open terrain, would have to be defended, even if only against irregular opposition forces. This territory could be contested for years until heavy vehicle and railway bridges over the Kerch Strait were built.

A third, even more ambitious, military-operational reason would be to seize and hold all of Ukraine’s Black Sea Coast, thus securing land communications to Transnistria. Such an operation would entail, at least, control of an additional 300–400 by 100km area.

What would indicate that an expansion of the Crimea operation is in preparation? One indication could be Russian complaints that Ukraine was hindering supplies to Crimea, causing the population to suffer, or preparing to take the peninsula back by force. On the military side, an indication would be a concentration of Russian ground forces able to take and hold such an area (all-arms armies with motor-rifle and tank brigades) supported by air and sea units, on top of those units now deployed in Crimea itself. Another possible indication of preparations for a larger ground operation would be an extension of military service of conscript soldiers in those units.

Holding on to territory would also entail Russia taking economic responsibility for the population and securing law and order. Kiev is unlikely to help with this and local pro-Russian strongmen may be unable to provide security. Russia would then have the option of deploying occupation forces. Interior Ministry troops could be used, but that would mean Russia would be unable to use them elsewhere, for example, in the North Caucasus. Reserves could be called up to man brigades that have equipment in store. Finally, forces from more remote areas such as the Russian Far East, the Kola Peninsula or Kaliningrad could be deployed. All these options would be time-consuming and cumbersome, and involve military-strategic risk-taking. Therefore they would be tell-tale signs that Russia was preparing for a longer or wider operation in Ukraine than the forces currently available could undertake.

What is available for a further military intervention?What military assets does Russia have available for operations in Ukraine? It is important to note that land battles are fought by units – all-arms armies, commanding brigades and battalions. Just counting soldiers and tanks does not give an accurate picture. Furthermore, force dispositions, manning levels and strategic mobility need to be considered. The analysis of available forces below draws on a previous FOI assessment of Russian military capability.

The annexation of Crimea has, to a degree, diluted Russia’s overall military capability. Securing Crimea militarily over time requires the reinforcement of the whole peninsula’s air and coastal defences, and ensuring the capability for combined-arms ground operations, primarily for defending the peninsula. A ground force of two motor-rifle brigades reinforced by artillery, air-defence units and attack helicopters would be needed, as well as the command function of an all-arms army. Russia’s Black Sea Fleet lacks the capability to command combined-arms ground operations. These assets would have to be taken from somewhere else in Russia.

Russia’s armed forces continued exercising in western and southern Russia all through March. The exercises kept up military pressure on other parts of Ukraine. Meanwhile, as of late March, Russian forces were busy reinforcing Crimea as well as augmenting and rotating forces. Lighter spearhead forces, such as airborne and special forces, are gradually being replaced by heavier infantry units. This could indicate concern about a Ukrainian military move against the peninsula. It could also be a way to make the spearhead forces available for another Crimea-style operation or to prepare for an offensive northward to expand the Crimea operation. However, this transition to heavier, standard units could also be the normal withdrawal of rapid-reaction spearhead forces, having successfully seized and held their objective.

As of late March, three of Russia’s four MDs had been involved in Ukraine-related activities. The nearby Southern MD has two armies, the 49th and 58th, of which the latter is the larger. There are indications that elements from the command-and-control support brigade of the 49th Army have deployed to Crimea, suggesting a strengthening of the ability to conduct larger ground operations than the previous command-and-control arrangements in Crimea could handle. The 58th Army is assessed to be committed to normal operations in the unstable North Caucasus. Despite the Southern MD nominally having nine manoeuvre brigades (motor-rifle and tank brigades), only the independent 20thMotor Rifle Brigade and one or two more brigades may be spared for operations in Ukraine.

The Western MD has two armies, the 20th (two tank brigades and two motor-rifle brigades; the divisions formed in this army in 2013 are counted as reinforced brigades) around Moscow and the 6th(two motor-rifle brigades) around St Petersburg. The former is the Western MD’s strongest ground-force unit and could be deployed to Ukraine, possibly reinforced by the Western MD’s independent 27th Motor Rifle Brigade. The 6th Army would then be needed as flank protection so that western Russia is not left wide open. Three brigade equipment sets (two motor rifle and one tank) could, as a consequence, be drawn out of stores to replace standing units deployed to Ukraine, although that would require moving personnel or calling in reserves. As noted above, forces from the Kola Peninsula or Kaliningrad will not make a difference in the short run, apart from being able to supply some personnel. However, manning levels of around 60% within the units reduces the number of brigades that can be deployed. In total, the Western MD could make a force equivalent of up to four manoeuvre brigades available for an operation.

The Central MD has two armies, the 41st in the east and the 2nd in the West. The latter was part of the early March readiness-check exercise and is likely to be deployable to Ukraine with one or two manoeuvre brigades fairly quickly. In addition, one brigade directly subordinated the Central MD could also be spared. The Eastern MD is probably too far away and has too few readily available units to be able to provide any significant forces for operations in Ukraine, especially in the short run. Thus Russia would be able to dispatch up to three manoeuvre brigades from the Central MD for an operation in Ukraine.

Among lighter forces the following are assessed to be available: three divisions and one brigade of Russia’s airborne forces (with another airborne division kept as a strategic reserve); four special forces brigades; the Black Sea Fleet Naval Infantry brigade; and up to two more Naval Infantry regiments.

In sum, Russia has the freedom of action to deploy within 10 days the 20th and 2nd armies to command operations in eastern Ukraine, with elements of the 49th Army deploying in Crimea. Altogether, the operation would include some seven to nine manoeuvre brigades and support units such as air defence, artillery and engineers. Each army would have at least two motor-rifle brigades under its command. In addition, up to 30,000 lighter forces are also available.

This sizeable force would nevertheless hardly be enough for securing land communications to Transnistria - by holding on to all of Ukraine’s Black Sea Coast - let alone holding on to eastern Ukraine in the face of Ukrainian armed resistance. However, it would suffice to expand the Crimea operation to create a buffer north of the peninsula and could perhaps be just enough to secure the supply infrastructure over time as well. The bigger the operational area, the more forces will be tied up long-term.

Repeating Crimea-style operations in other parts of Ukraine would initially require mainly light forces for the actual intervention, with heavier infantry units massing on Ukraine’s borders being prepared to follow and secure the areas taken by the light forces. The more places in which such operations are performed, the more forces will be tied up there.

Military-strategic risks associated with a larger involvement in UkraineWhat if Russia was to try to seize and hold eastern Ukraine or push all along the Black Sea coast to Transnistria? If it were using only the resources available today, while expecting armed resistance, this would mean taking a higher risk. If Russia were to commit more forces than three armies, commanding some seven to nine manoeuvre brigades, it could invite military-strategic risks on top of that which might be posed within Ukraine itself. Where should Russia take that military-strategic risk? Whilst the world’s focus is on Crimea and Ukraine, other parts of Russia and its neighbourhood are not all peaceful. Russia’s force commitments include primarily the Caucasus and Central Asia, both volatile regions.

Russia’s armed forces are deployed all across the North Caucasus and in three brigade-size bases in Georgia and Armenia in the South Caucasus. Russia must also be able to uphold its security commitments to its ally Armenia within the framework of the CSTO (Collective Security Treaty Organization). The risk of an Azeri-Armenian conflict over Nagorno-Karabakh has not gone away. The bases are likely to be tied to their present tasks and their troops unlikely to be sent elsewhere to any great extent. In the North Caucasus, Dagestan and Chechnya are but two areas where forces may be needed. Another problem for Russia in the North Caucasus is the influence of militant Islam, which is also seen in more central parts of Russia, such as Tatarstan. The Southern MD, which encompasses these areas, has the highest readiness in terms of personnel and the proportion of modern equipment. This is where Russia’s armed forces have been expected to have to fight at short notice. One less unit here could perhaps lead to a higher security risk than in other MDs. Furthermore, additional regional instability may arise from adjacent areas south of the Caucasus, in the wider Middle East.

All the former Soviet republics in Central Asia are arguably inherently volatile, for reasons that range from pending succession struggles to corruption and near-state failure. The situations in Tajikistan and Kyrgyzstan in particular could deteriorate quickly. Long before the events of Maidan square in Ukraine, Russian observers noted the risk of events similar to those of the Arab Spring causing instability in Central Asia. Here as well, Russia has commitments under the CSTO to Kazakhstan, Kyrgyzstan and Tajikistan. With NATO leaving Afghanistan, and China seemingly uninterested in military intervention, the CSTO is the only organisation actively preparing to intervene with military forces in Central Asia.

The CSTO’s military capabilities are essentially Russia’s; both upholding regional groups of forces in Central Asia and the Caucasus and for the rapid reaction element, the Collective Operational Reaction Forces built primarily around Russia’s 98th Airborne Division and 31st Airborne Brigade – units that have been deployed either to Crimea or to exercises near Ukraine. Nevertheless, the capability of these CSTO forces has not been reduced significantly and furthermore when Russian units from these airborne forces in Crimea have been replaced, it is assessed that Russia will have full freedom of action with them shortly thereafter. However, if they are detailed for an extended operation in Ukraine they will be unavailable for other missions.

In Tajikistan, Russia’s brigade-size 201st Military Base in Dushanbe would likely be able initially to handle disturbances in the country. But prolonged or wider unrest in the region, for example cross-border tensions in the Fergana Valley, may require Russian reinforcements, primarily from the Central MD, which commands operations in Central Asia.

In the west, the potential threat from NATO would not diminish in the event of further Russian military invention in Ukraine. Nuclear and conventional stand-off weapons could provide some deterrence, but they would need to be backed up by ground-force units. In the east, Russian forces’ numerical inferiority to China’s People’s Liberation Army would be accentuated if ground-force units were to be deployed from there to the west.

Consequences for military securityRetaining Crimea would likely require up to two manoeuvre brigades with additional support units. Russia would likely be able to manage such a deployment, but doing so would nevertheless reduce Russia’s ability to handle instability elsewhere, primarily in the Caucasus and Central Asia.

If Russia decides to solve Crimea’s supply problems by securing a land corridor or seizing a larger buffer zone, two to three more armies may be needed, first to push into territory but probably also over time to secure that taken. Most of Russia’s available forces west of the Urals would then be needed. This would weaken not only Russia’s response capability but also its initial capability to handle instability in volatile areas. It would also affect Russia’s balance of forces with NATO and perhaps even with China in the Far East. If Russia gets bogged down in Ukraine, this will affect its long-term ability to handle its military-strategic environment. Such operations, if successful, would leave Russia with freedom of action primarily with its airborne forces, Special Forces, and stand-off warfare assets.

If the forces available as reinforcements in quickly-emerging local and regional wars are reduced by the commitment of Russian forces to Ukraine, the threshold for the use of non-conventional military means might also be lowered. Additionally, in our assessment the Russian concept of nuclear de-escalation, i.e. using a few tactical nuclear devices to deter an adversary from further escalation, is especially worrying in this context.

In conclusion, there are military-strategic reasons for Russia not committing additional forces to an extended operation in Ukraine. The risk of military overstretch is significant if forces get bogged down. Even the less ambitious options outlined, such as repeating Crimea-style operations elsewhere, would tie up a considerable share of Russia’s available forces west of the Urals. However, it should be noted that this may not prevent the political leadership from deciding to intervene on a wider scale. Furthermore, if Russian military planners do not expect any significant armed resistance in Ukraine, the risk of temporarily committing forces for a large-scale invasion may be considered acceptable in view of the prospective gains. However, forecasting the size and duration of military force commitments is difficult, as both the Soviet and NATO operations in Afghanistan and the Russian counter-insurgency operations in Chechnya have shown.

Johan Norberg and Fredrik Westerlund are Senior Researchers at FOI, the Swedish Defence Research Agency